A catch-all email mailbox is one that collects all the messages sent to invalid email addresses. For instance, if your email address is email@example.com, but somebody mistypes it and sends a message to firstname.lastname@example.org, it will still be received in the catch-all mailbox that you have set up. Just one single mailbox per domain can have this feature activated and in this way you’ll never miss messages because the other side has an obsolete email address or has made a mistake. The negative aspect of setting up a catch-all mailbox is that you may begin receiving a lot of junk email messages, but this issue can be fixed by using an anti-spam protection solution. It’s also vital to bear in mind that a mailbox with an activated catch-all feature cannot redirect incoming messages to a third-party email address.